Method of making haloids.



JAMES C. GRAVES, 0F MIDLAND, MICHIGAN, AND JOHN P.

DOW CHEMICAL COMPANY, OF

OHIO, ASSIGNORS TO THE CORPORATION OF MICHIGAN.

No Drawing;

To all whom it may concern:-

Be -it known that we, and JOHN P. Snroxs, both citizens of the UnitedStates, residents of Midland, county of Midland, and State of Michigan,and of Cleveland, county of Cuyahoga, and State of Ohio, have jointlyinvented a new and useful Improvement in Methods of Making Haloids, ofwhich the following is a specification, the principle of the inventionbeing herein explained and the best mode 1n wlnch we have contemplatedap.

plying that principle, so it from other inventions.

The present invention, relating, as indicated, to the making of haloids,has more particular regard to the manufacture of such compounds byreduction of the corresponding tri-oxygcu salt. in other words, suchprocess relates to the making of a chlorid, bromid or iodid From achlorate, bromate, or iodate, specifically a bromate, chlorate, oriodate of an alkali or of an alkaline earth. Said invention, thenconsists of the means and steps hereinafter fully described andparticularly pointed out in the claims.

\Vhen bromin combines with potassium hydrate or carbonate some potassiumbromate is formed and at the same time a little hypobromite. Thishypobromite, however, readily goes over to the bromate partially in thecold and completely on heating. In order to recover pure potassiumbromid from the resulting mixture of potassium bromid and bromate theprevailing process heretofore has been to heat such mixture to a redheat. This of course involves the preliminary evaporation of thesolution of bromid and and then subsequently raising the same to suchred heat, as a result of which not only is a considerable mechanicalloss incurred incidentally to handling the material but also more orless loss through volatilization in the heating operation.

The object of the present invention is to substitute for suchevaporating to dryness as to distinguish and subsequent heating, a wetprocess that will produce a precipitate susceptible of being easilyWashed free from accompanying bromid. We are aware that potassium bromidhas been prepared by a wet process by the action of-bromld of 1ron oneither potassium hydrate or potass um carbonate;

Specification of Letters Patent.

JAMES C. GRAVES bromate to dryness.

SIMONS, 0F CLEVELAND, MIDLAND, MICHIGAN, A

-METHOD OF MAKING- EALOIDS.

potash by our improved process the mixture of potas Patented July 112,1910. Application filed August 6, 1909. Serial No. 511,511.

sium bromid, bromate and hypobromite in solution is charged into a tank,together with a quantity of finely divided iron. This tank contains anagitator that-revolves near the bottom of the tank so that the iron ismixed with the solution and is prevented from subsiding and forming acompact mass on the bottom. The following reaction thereupon takes placebetween the bromate and the iron KBrOH-Fe :KBr-l-Fe O This reaction isaccompanied by the liberation of considerable heat, which decomposes anyremaining hypobromites, converting them into bromid and bromate. Theagitation of the iron and liquor is continued until all the bromate isreduced, external heat being applied if found necessary. The solidmaterial remaining in the tank is largely a dense iron oxid that iseasily washed free from the accompanying liquor by filtration, andwashing methods, well known to persons versed in chemical manufacture.This method is applicable in the same way to the reduction of otherbromates such as those of sodium, calcium, strontium and barium, thereactions being as follows \Vhile we have described the application ofour invention to the reduction of a bromate to a bromid, it is equallyapplicable to the similar reduction of otherv tri oxygensalts, chloratesand iodates. The following reactions will serve as illustrations KClO+Fe :KCl-i-Fe O N2II() .,+FG2INHI+FO2O3 An important application of thefirst and above is to be found in the electrolytic alkali industry inthe elimination of chlorates of potassium or sodium from the brine fedto the cells. This chlorate enters as a necessary evil in this industrydue-to the second ary reactions which take place between the principalproducts of electrolysis, i. e. caustic and chlorin. In practice, onlyapart of the chlorid fed to'a cell is converted into caustic andchlorin, and when the cathode efiiuent, which contains the causticproduced by the electrolysis together with the unde composed chlorid andsome chlorate, both in solution, is concentrated by boiling, suchchlorid separates out. This separated salt carries a part of thechloratepresent in the cell efiluent, and when it is re-dissolved andadded to fresh chlorid to make fresh brine for the cell, thecontaminating chlorate is also dissolved. If Suchcontaminated solutionbe then'fed to the cell, excessive electrode consumption and loweredeconomy will result. We have found that if such contaminated solution betreated with finely divided iron as hereinbefore described, with theaplication of heat, if necessary, the

chlorate will be reduced to chlorid with precipitation of the oxid ofiron, and a substantially pure solution of the haloid secured. It willof course be understood that other suitable means for bringing the ironand the bromate, or other salt, together may be employed instead of theone hereinbefore described, but such described means have been foundconvenient and satisfactory in practice. The iron which we use ispreferably cast iron and is best employed, as has been stated, in more:or less finely divided form, machine borings serving admirably forthispurpose. The application of heat 15 not necessary but hastens thereaction, a temperature of 90 degrees centigrade being recommended. Thetime required to reduce 600 lbs. of the bromate will under favorableoperative conditions be between 8 and 12 hours.

Other modes of applying the principle of our invention may be employedinstead of the one explained, change being made as re gardsthe processherein disclosed, provided the steps stated by any one of the followingclaimsor the equivalent of such stated step water solution with finelydivided cast iron.

water solution with finely divided cast iron.

5. The method of making potassium chlorid from potassium chlorate, whichconsists in treating the said chlorate in a water solution with metalliciron.

6. In the electrolytic production of alkalies from their haloidcompounds, the steps which consist in recovering the haloid from thecell effluent, and then eliminating the tri-oxygen salt of the halogenfrom such haloid, substantially as described.

7. In the electrolytic production of alkalies from their haloidcompounds, the steps which consist in recovering the haloid from thecell efiluent, and then eliminating the tri-oxygen salt of the halogenfrom such haloid by treating the same ina water solution with metalliciron.

8. In the electrolytic production of alkalies from their haloidcompounds, the steps which consist in recovering the haloid from thecell efliuent, and then eliminating the tri-oxygen salt of the halogenfrom such haloid by treating the same in a water solution with finelydivided cast iron.

9. In the electrolytic production of alkalies from their chlorids, thesteps which consist in recovering the chlorid from the cell effluent,and then eliminating the chlorate from such chlorid, by treating thesame with metallic iron.

10. The method of making a haloid from tion with finely divided castiron, whereby the latter is precipitated as a dense oxid, and thenwashing such. oxid.

Signed by JAMES C. GRAVES, this 8th day of July, 1909.

JAMES C. GRAVES.

Attested by HARBEN H, Dow,

RUPERT E. PARIS.

Signed by J OHN P. SIMoNs, this 3 day of August, 1909.

JOHN sIMoNs' Attested by D. T. DAVIES, H. F. HADDE,

consists in treating said salt in a water solu-

